(1) Field of the Invention
The present invention relates to a device for maintaining the altitude of a payload the altitude-maintenance energy source of which is permanent and extracted from the medium.
(2) Description of the Related Art
According to America's NASA documents, a “HALE” (“High Altitude, Long Endurance”) platform is known that supports observation and telecommunication systems as its payload. This platform essentially comprises a light body in the form of a very elongate rectangle, covered on its upper face with a large number of solar panels powering propulsion propeller engines, which maintain its altitude, but because the propulsion is provided only by solar panels, this platform has a limited service life.
According to document WO 2007/107018 A1, a stand-alone stratospheric platform is known for maintaining the altitude of a payload, but this platform, because it uses parachutes or paragliders as its carrying surfaces, does not have sufficient aerodynamic qualities to remain geostationary for a long period.